When investigating deaths due to stab wounds, a common question asked to the forensic pathologist concerns the force required to inflict a given wound.In this study, tests were performed on 6 human cadavers. A material testing machine was used to produce the stab wounds and to record the force required to penetrate skin, muscle, cartilage, and rib bone of the chest. Three different blades were used: a steak knife, a butcher knife, and a lock-blade knife. On each cadaver, chest injuries were produced at the following locations: (a) skin, intercostal soft tissues; (b) skin, muscle, and cartilage; and (c) skin, muscle, and bone. After the experiment, a chest dissection was performed to confirm the correct locations of the produced stab wounds.The force required to insert a knife into cartilage or bone was significantly greater than the force to insert it into a region only covered by skin. There was wide variation in the force required to insert a knife into different bodies, but no force for any knife at any location for all bodies was greater than 261 N.This study allowed us to obtain quantitative measures of the force required to penetrate human chest tissues, removing subjective factors.
Myxopapillary ependymoma (MPE) is a relatively common neoplasm arising primarily in the filum terminale/lumbosacral region of the spinal cord. It is designated as a grade I tumor in the most recent WHO Classification of Tumours of the CNS, although aggressive clinical behavior can be observed, especially in cases arising in an extradural location. Anaplastic transformation in MPE is exceedingly rare with <20 examples reported in the English literature, and consensus on diagnostic features and definitive grading remain to be determined. Here, we present 2 cases of recurrent MPE with anaplastic features, both of which had histology consistent with conventional MPE as well as areas with significant atypia, frequent mitotic figures, elevated Ki-67 proliferation indices (>10%–50%), necrosis, and focal vascular proliferation. Targeted next-generation sequencing panels revealed no definitive pathogenic mutations or fusion proteins in either case. Copy number profiling, methylation profiling, and t-Distributed Stochastic Neighbor Embedding were performed to investigate the molecular characteristics of these tumors. To the best of our knowledge, these are the first reported cases of MPE with anaplastic features with methylation profiling data. In addition, we review the literature and discuss common histologic and molecular findings associated with anaplastic features in MPE.
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